5 letters:
autor, autre, botar, katar, mater, otter, water

6 letters:
agotar, anotar, azotar, battre, botter, cauter, cotter, datter, dotter, f.i.r., flotar, gotter, h.e.r., hotter, j.a.r., jotter, kotter, lawter, lotter, mahtar, motter, notter, o.a.r., potter, quatar, quater, rotter, totter, vawter, watter, zotter

7 letters:
allotir, blotter, bowater, bywater, clotter, flawter, flotter, frotter, got her, knotter, newater, not her, piotter, plotter, sautter, slotter, snotter, spotter, stotter, swatter, swotter, trotter, yachter

8 letters:
allotter, boughter, cutwater, daughter, eyewater, formater, mccotter, pomwater, redwater, seawater, shot her, spotter', squatter, tarwater

9 letters:
backwater, bathwater, bayswater, bluewater, boycotter, coldwater, deepwater, dishwater, edgewater, fairwater, feedwater, firewater, fitswater, flatwater, flaughter, goldwater, goodwater, graywater, greywater, headwater, highwater, hot-water, ice water, jerkwater, limewater, low water, meltwater, mid-water, milkwater, overwater, pia mater, pinkwater, pinquater, polywater, pomewater, porewater, rainwater, red water, rosewater, saltwater, schlotter, sea otter, sidewater, slaughter, tailwater, tap water, teeswater, thelotter, tidewater, ullswater, wastwater, wirewater

10 letters:
alma mater, back-water, bath water, bilgewater, blackwater, blendwater, blue-water, bogtrotter, bought her, breakwater, bridgwater, broadwater, catchwater, caught her, clearwater, cold-water, complotter, deep-water, ditchwater, drinkwater, dura mater, floodwater, flyswatter, forgot her, freshwater, hard water, heartwater, high-water, high water, holy water, imprimatur, lime-water, make water, pass water, phycomater, pinspotter, rose-water, rose water, salt-water, sandlotter, shearwater, sheerwater, smartwater, soda-water, soda water, soft water, sought her, southwater, stillwater, stormwater, straughter, sweetwater, tail-water, take water, taught her, underwater, wastewater, well water, whitewater

11 letters:
annunciator, bilge-water, break water, bridgewater, brightwater, brought her, first water, fly-swatter, fresh-water, fresh water, gastrolater, gillenwater, goddaughter, groundwater, heavy water, magna mater, river otter, rough water, sewer water, shotspotter, slack water, springwater, spurn-water, sugar water, thought her, tonic water, vichy water, white-water, white water

12 letters:
a.n.s.w.e.r., barley-water, barley water, branch water, derwentwater, fallingwater, grandaughter, ground water, lily-trotter, making water, manslaughter, spring water, stepdaughter, strong-water, teetertotter, toilet water, trainspotter, trendspotter, ziment-water

13 letters:
ammonia water, body of water, cologne water, cybersquatter, globe-trotter, granddaughter, mineral water, passing water, quinine water, step-daughter, surfeit-water, take in water, teeter-totter, tetter-totter, titter-totter

14 letters:
chlorine water, cynthia potter, drinking water, eurasian otter, grand-daughter, milk-and-water, police blotter, s.t.a.l.k.e.r., self-slaughter, treading water

15 letters:
distilled water, foster-daughter, sparkling water

16 letters:
carbonated water, danny drinkwater

17 letters:
lady in the water, mother's daughter, territorial water

18 letters:
sibanye-stillwater, the shape of water

19 letters:
great-granddaughter

20 letters:
bourton-on-the-water

21 letters:
blow out of the water

22 letters:
places in harry potter

23 letters:
come hell or high water

9 letters:
pis aller